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Unformatted text preview: Angel: Interactive Computer Graphics, Fourth Edition Chapter 6 Solutions 6.1 Point sources produce a very harsh lighting. Such images are characterized by abrupt transitions between light and dark. The ambient light in a real scene is dependent on both the lights on the scene and the reﬂectivity properties of the objects in the scene, something that cannot be computed correctly with OpenGL. The Phong reﬂection term is not physically correct; the reﬂection term in the modified Phong model is even further from being physically correct. 6.3 If we were to take into account a light source being obscured by an object, we would have to have all polygons available so as to test for this condition. Such a global calculation is incompatible with the pipeline model that assumes we can shade each polygon independently of all other polygons as it ﬂows through the pipeline. 6.5 Materials absorb light from sources. Thus, a surface that appears red under white light appears so because the surface absorbs all wavelengths of...
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This note was uploaded on 01/25/2011 for the course CSCI 6821 taught by Professor Alxe during the Spring '10 term at Georgia Southwestern.
- Spring '10
- Computer Graphics